Timing of methamphetamine exposure during adolescence differentially influences parvalbumin and perineuronal net immunoreactivity in the medial prefrontal cortex of female, but not male, rats.

INTRODUCTION: Adolescence involves significant reorganization within the medial prefrontal cortex (mPFC), including modifications to inhibitory neurotransmission that may be mediated through parvalbumin (PV) interneurons and their surrounding perineuronal nets (PNNs). These developmental changes, which can result in increased PV neuron activity in adulthood, may be disrupted by drug use resulting in lasting changes in mPFC function and behavior. Methamphetamine (METH), which is a readily available drug used by some adolescents, increases PV neuron activity and could influence the activity-dependent maturational process of these neurons. METHODS: In the present study, we used male and female Sprague Dawley rats to test the hypothesis that METH exposure influences PV and PNN expression in a sex- and age-specific manner. Rats were injected daily with saline or 3.0 mg/kg METH from early adolescence (EA; 30-38 days old), late adolescence (LA; 40-48 days old), or young adulthood (60-68 days old). One day following exposure, effects of METH on PV cell and PNN expression were assessed using immunofluorescent labeling within the mPFC. RESULTS: METH exposure did not alter male PV neurons or PNNs. Females exposed in early adolescence or adulthood had more PV expressing neurons while those exposed in later adolescence had fewer, suggesting distinct windows of vulnerability to changes induced by METH exposure. In addition, females exposed to METH had more PNNs and more intense PV neuron staining, further suggesting that METH exposure in adolescence uniquely influences development of inhibitory circuits in the female mPFC. CONCLUSIONS: This study indicates that the timing of METH exposure, even within adolescence, influences its neural effects in females.

ErbB4 signaling in dopaminergic axonal projections increases extracellular dopamine levels and regulates spatial/working memory behaviors.

Genetic variants of Neuregulin 1 (NRG1) and its neuronal tyrosine kinase receptor ErbB4 are associated with risk for schizophrenia, a neurodevelopmental disorder characterized by excitatory/inhibitory imbalance and dopamine (DA) dysfunction. To date, most ErbB4 studies have focused on GABAergic interneurons in the hippocampus and neocortex, particularly fast-spiking parvalbumin-positive (PV+) basket cells. However, NRG has also been shown to modulate DA levels, suggesting a role for ErbB4 signaling in dopaminergic neuron function. Here we report that ErbB4 in midbrain DAergic axonal projections regulates extracellular DA levels and relevant behaviors. Mice lacking ErbB4 in tyrosine hydroxylase-positive (TH+) neurons, but not in PV+ GABAergic interneurons, exhibit different regional imbalances of basal DA levels and fail to increase DA in response to local NRG1 infusion into the dorsal hippocampus, medial prefrontal cortex and dorsal striatum measured by reverse microdialysis. Using Lund Human Mesencephalic (LUHMES) cells, we show that NRG/ErbB signaling increases extracellular DA levels, at least in part, by reducing DA transporter (DAT)-dependent uptake. Interestingly, TH-Cre;ErbB4f/f mice manifest deficits in learning, spatial and working memory-related behaviors, but not in numerous other behaviors altered in PV-Cre;ErbB4f/f mice. Importantly, microinjection of a Cre-inducible ErbB4 virus (AAV-ErbB4.DIO) into the mesencephalon of TH-Cre;ErbB4f/f mice, which selectively restores ErbB4 expression in DAergic neurons, rescues DA dysfunction and ameliorates behavioral deficits. Our results indicate that direct NRG/ErbB4 signaling in DAergic axonal projections modulates DA homeostasis, and that NRG/ErbB4 signaling in both GABAergic interneurons and DA neurons contribute to the modulation of behaviors relevant to psychiatric disorders.

Gßγ subunit activation promotes dopamine efflux through the dopamine transporter.

The dopamine transporter (DAT) is an important regulator of brain dopamine (DA) homeostasis, controlling the intensity and duration of DA signaling. DAT is the target for psychostimulants-like cocaine and amphetamine-and plays an important role in neuropsychiatric disorders, including attention-deficit hyperactivity disorder and drug addiction. Thus, a thorough understanding of the mechanisms that regulate DAT function is necessary for the development of clinical interventions to treat DA-related brain disorders. Previous studies have revealed a plethora of protein-protein interactions influencing DAT cellular localization and activity, suggesting that the fine-tuning of DA homeostasis involves multiple mechanisms. We recently reported that G-protein beta-gamma (Gßγ) subunits bind directly to DAT and decrease DA clearance. Here we show that Gßγ induces the release of DA through DAT. Specifically, a Gßγ-binding/activating peptide, mSIRK, increases DA efflux through DAT in heterologous cells and primary dopaminergic neurons in culture. Addition of the Gßγ inhibitor gallein or DAT inhibitors prevents this effect. Residues 582 to 596 in the DAT carboxy terminus were identified as the primary binding site of Gßγ. A TAT peptide containing the Gßγ-interacting domain of DAT blocked the ability of mSIRK to induce DA efflux, consistent with a direct interaction of Gßγ with the transporter. Finally, activation of a G-protein-coupled receptor, the muscarinic M5R, results in DAT-mediated DA efflux through a Gßγ-dependent mechanism. Collectively, our data show that Gßγ interacts with DAT to promote DA efflux. This novel mechanism may have important implications in the regulation of brain DA homeostasis.

Timing of methamphetamine exposure during adolescence differentially influences parvalbumin and perineuronal net immunoreactivity in the medial prefrontal cortex of female, but not male, rats.

Adolescence involves significant reorganization within the medial prefrontal cortex (mPFC), including modifications to inhibitory neurotransmission mediated through parvalbumin (PV) interneurons and their surrounding perineuronal nets (PNNs). These developmental changes, which result in increased PV neuron activity in adulthood, may be disrupted by drug use resulting in lasting changes in mPFC function and behavior. Methamphetamine (METH), which is a readily available drug used by some adolescents, increases PV neuron activity and could influence the activity-dependent maturational process of these neurons. In the present study, we used male and female Sprague Dawley rats to test the hypothesis that METH exposure influences PV and PNN expression in a sex- and age-specific manner. Rats were injected daily with saline or 3.0 mg/kg METH from early adolescence (EA; 30-38 days old), late adolescence (LA; 40-48 days old), or young adulthood (60-68 days old). One day following exposure, effects of METH on PV cell and PNN expression were assessed using immunofluorescent labeling within the mPFC. METH exposure did not alter male PV neurons or PNNs. Females exposed in early adolescence or adulthood had more PV expressing neurons while those exposed in later adolescence had fewer, suggesting distinct windows of vulnerability to changes induced by METH exposure. In addition, females exposed to METH had more PNNs and more intense PV neuron staining, further suggesting that METH exposure in adolescence uniquely influences development of inhibitory circuits in the female mPFC. This study indicates that the timing of METH exposure, even within adolescence, influences its neural effects in females.

Evaluation of Eye Safety Protocol in the Dental Office.

Background: Ocular health is significant as undetected and untreated eye conditions can lead to vision loss and blindness. Usually, dentists, dental assisting staff, and patients undergoing frequent dental corrections are likely affected by eye injuries. Methods: This survey aimed to evaluate eye safety protocols in the dental fraternity. A prevalidated questionnaire was given to practicing graduate and postgraduate dentists to obtain details of the eye safety protocol they adopted. Results: A total of 150 dentists approached; only 125 chose to participate in the survey and answered our questionnaire. Although most dentists used eye protection for themselves, primarily personal eyeglasses and face shields, eye injury was quite common in them. Conclusion: Data from this study revealed that the use of eye safety practices among the respondents could be improved. Clinicians should be aware that they are responsible for providing adequate eye protection for themselves and their assisting staff and patients.

Relationship Between Body Mass Index, Occlusion, and Dental Caries among School Children in Riyadh.

Background: Malocclusion and lifestyle diseases like obesity can lead to poor oral hygiene and food stagnation, resulting in increased caries incidence. Objectives: To evaluate the interrelationship of age, body mass index (BMI), occlusion, and dental decay in children aged between 5 and 14. Methodology: Our study included 423 school students aged 5-14 visiting dental clinics. Correlation between BMI and DMFT index using Spearman's correlation coefficient and the association of BMI with gender, age group, and occlusion using the Chi-square test were assessed. Results: The study comprised a larger sample of students aged above 10 years (n = 217) and between 6 and 10 years (n = 183), with Angle's Class I and II malocclusion being predominant. A weak positive correlation was found between BMI and the missing component of the DMFT index, while significant statistical associations were observed between underweight students below 5 years (8.5%) and obesity in those between 6 and 8 years (53.3%) (P < 0.05). Conclusion: Dental practitioners must pay attention to the BMI of children and consider diet as a major intervention for dental caries prophylaxis.

Analysis of postural balance between two aquatic sports using vertical vs. horizontal body position.

OBJECTIVE: This study aims to analyze and compare the postural balance between two aquatic sports where vertical vs. horizontal body positions (i.e., windsurfing vs. swimming) are key techniques for both sports. SUBJECTS AND METHODS: Eight volunteer windsurfers and eight swimmers agreed to participate in this study. Each of the assessments was a 2D kinematic analysis of frontal and/or sagittal balance (i.e., in bipedal and/or unipedal stance) of the center of mass velocity on wobble board (Single Plane Balance Board) on hard and/or soft surface. Kinematic analysis was performed in 2D using two action-cams. Data were digitized using the video-based data analysis system SkillSpector. RESULTS: The results showed that the ANOVA, with repeated measures on 1 factor, showed a significant difference (p<0.001) between groups (i.e., swimmers and windsurfers) in all variables and in the interaction between ground (i.e., hard and foam) and group (p<0.01) in all tests in sagittal plane. Furthermore, for the ground*group interaction, a study (i.e., paired t-test) of the difference between balance (i.e., in frontal and/or sagittal plane) on hard and soft ground for each group showed that windsurfers had no difference in body sway in frontal and/or sagittal plane between hard and soft surface in bipedal stance. CONCLUSIONS: We concluded that the windsurfers showed better postural balance performances compared to swimmers in the bipedal posture on hard and soft ground. Also, the windsurfers presented a better stability level compared with the swimmers.

Effect of glissade-step on kinetic and kinematic variables of stag ring leaps with and without throw-catch of the ball in rhythmic gymnastics.

This study focuses on certain characteristics of the jump take-offs in rhythmic gymnastics (RG). Rhythmic gymnasts always perform their jumps with the same preferred run-up technique, proceeded by a chassé-step in most of the cases. The overall idea was to analyse other step-techniques that could be performged on one-leg, which could prepare jumps. The aim of this study was to compare kinetic and kinematic variables between three-stag ring leaps with and without throwing-ball, performed using the glissade-step as a preparatory phase for take-off with one-leg these were as follows: glissade stag ring leap without-ball (GSWB), throw-ball glissade stag ring leap (TBGS) and glissade throw-ball stag ring leap (GTBS). Seven members of the Tunisian RG national team took part in this study. The technical elements were recorded in 2D using two-cameras on a specially designed floor carpet where a force-plate was integrated. The results showed that the three-leaps had significant impacts on the performance variables, especially on the force, the velocity and the flexibility. The GTBS was the most effective leap as the throw took place during the jump, which has increased its technicality and the applied physical variables, the vertical force, the rate of force development, the horizontal and vertical velocities and displacements.

Phenotyping and Genotyping Evaluation of E. coli Produces Carbapenemase Isolated from Cancer Patients in Al-Basrah, Iraq.

One of the most important nosocomial organisms that cause urinary tract infections (UTIs) in cancer patients is Escherichia coli. A significant cause of concern in managing UTIs is the development of carbapenem-resistant bacteria. Escherichia coli with carbapenem resistance has become a more serious problem, particularly in Iraq. In this regard, the present study aimed to estimate the prevalence of carbapenem-resistant E. coli in Al-Basrah, Iraq. Conventional tests and the Vitek®2 system were used to identify the isolates and determine the susceptibility of E.coli isolates to antimicrobials. In addition, E.coli isolates were tested by mCIM and eCIM methods. Moreover, the major carbapenemase genes, including blaSPM, blaIMP, blaVIM, and blaKPC were detected by polymerase chain reaction. In total, 120 urine samples were collected from cancer patients who were suspected of having urinary tract infections at Basrah Center of Oncology Al-Sader Teaching Hospital, Basrah, Iraq. Identification of bacterial growth by using biochemical tests revealed different bacterial species. The most frequent bacteria were E. coli (n=22, 53.65%) isolates. The results showed that 13 (59.09%) and 11 (50%) out of 22 E. coli isolates were positive for the production of carbapenemase, based on the eCIM and sCIM, respectively. The majority of E.coli in this study possessed the blaVIM gene (n=13, 59.1%), followed by the blaKPC gene (n=5, 22.73%), blaIMP gene (n=5, 22.73%), and blaSPM gene (n=4, 18.18%). There is a spread of more than one type of carbapenemase among the E. coli isolates collected from UTI cancer patients in Basrah Hospital. The E. coli identified in the current study had a strong capacity to produce carbapenemase enzymes against the four generations of antibiotics, including imipenem and meropenem antibiotics.

Brief postnatal exposure to bisphenol A affects apoptosis and gene expression in the medial prefrontal cortex and social behavior in rats with sex specificity.

Bisphenol A (BPA) is an endocrine disruptor found in polycarbonate plastics and exposure in humans is nearly ubiquitous and it has widespread effects on cognitive, emotional, and reproductive behaviors in both humans and animal models. In our laboratory we previously found that perinatal BPA exposure results in a higher number of neurons in the adult male rat prefrontal cortex (PFC) and less play in adolescents of both sexes. Here we examine changes in the rate of postnatal apoptosis in the rat prefrontal cortex and its timing with brief BPA exposure. Because an increased number of neurons in the PFC is a characteristic of a subtype of autism spectrum disorder, we tested social preference following brief BPA exposure and also expression of a small group of genes. Males and females were exposed to BPA from postnatal days (P) 6 through 8 or from P10 through 12. Both exposures significantly decreased indicators of cell death in the developing medial prefrontal cortex in male subjects only. Additionally, males exposed to BPA from P6 - 8 showed decreased social preference and decreased cortical expression of Shank3 and Homer1, two synaptic scaffolding genes that have been implicated in social deficits. There were no significant effects of BPA in the female subjects. These results draw attention to the negative consequences following brief exposure to BPA during early development.

Region- and age-specific effects of perinatal phthalate exposure on developmental cell death and adult anatomy of dorsal and ventral hippocampus and associated cognitive behaviors.

Humans are exposed to phthalates, a class of endocrine-disrupting chemicals used in food packaging/processing, PVC plastics, and personal care products. Gestational exposure may lead to adverse neurodevelopmental outcomes. In a rat model, perinatal exposure to an environmentally relevant mixture and dose of phthalates leads to increased developmental apoptosis in the medial prefrontal cortex (mPFC) and a subsequent reduction in neurons and in cognitive flexibility measured in adults of both sexes (Sellinger et al., 2021b; Kougias et al., 2018b). However, whether these effects generalize to other cognitive regions, like the hippocampus, is less well understood as existing studies used single phthalates at large doses, unrepresentative of human exposure. In the current study, patterns of naturally occurring cell death were first established in the dorsal and ventral hippocampal subfields (CA3 and CA1). Both dorsal and ventral CA3 reached high levels of cell death on P2 while levels in dorsal and ventral CA1 peaked on P5 in both sexes. Exposure to a phthalate mixture (0.2 and 1 mg/kg/day) throughout gestation through postnatal day 10 resulted in subtle age- and region-specific decreases in developmental cell death, however there were no significant changes in adult neuron number or associated behaviors: the Morris water maze and social recognition. Therefore, perinatal exposure to a low dose mixture of phthalates does not result in the dramatic structural and behavioral changes seen with high doses of single phthalates. This study also adds to our understanding of the distinct neurodevelopmental effects of phthalates on different brain regions.

Perinatal phthalate exposure increases developmental apoptosis in the rat medial prefrontal cortex.

Phthalates are a class of endocrine disruptors found in a variety of consumer goods, and offspring can be exposed to these compounds during gestation and lactation. Our laboratory has found that perinatal exposure to an environmentally relevant mixture of phthalates resulted in a decrease in cognitive flexibility and in neuron number in the adult rat medial prefrontal cortex (mPFC). Here, we examine effects of phthalate treatment on prenatal cellular proliferation and perinatal apoptosis in the mPFC. To examine the phthalate effects on cellular proliferation, dams consumed 0, 1, or 5 mg/kg of the phthalate mixture daily from embryonic day 2 (E2) through the day of birth (P0), and on E16 and E17, they were injected with BrdU. The mPFC of offspring was analyzed on P5 and showed a decrease in labelled cells in the phthalate exposed groups. To examine whether changes in BrdU density observed on P5 were due to altered cell survival, cell death was measured on E18, P0, and P5 using a TUNEL assay in a separate cohort of prenatally exposed offspring. There was an increase in TUNEL labelled cells at E18 in the phthalate exposed groups. In the final experiment, dams consumed the phthalate mixture from E2 through P10, at which time mPFC tissue was stained with TUNEL. Phthalate treated subjects showed a higher density of apoptotic cells at P10. These results indicate both pre- and postnatal phthalate exposure increases apoptosis in the male and female rat mPFC. While the impact of phthalates on proliferation cannot be ruled out, these data do not allow for definitive conclusions.

Determinants of breastfeeding practice in Pujehun district, southern Sierra Leone: a mixed-method study.

BACKGROUND: It is well established that exclusive breastfeeding can play a critical role in reducing child morbidity and mortality. Limited research has been done thus far on the practice and perceptions of breastfeeding in Sierra Leone, where more than 10 % of children die before the age of five. This study aimed to gain understanding into and explore both matters in order to develop recommendations for effective strategies to promote breastfeeding practice in Pujehun District, Southern Sierra Leone. METHODS: This exploratory mixed-method study included a cross-sectional survey of 194 mothers, semi-structured interviews and focus group discussions. Logistic regression analysis was used calculated odds ratios of factors associated with primarily breastfeeding practice, defined as 'Children under six months of age who are fed with breast milk only and children older than six months of age that were exclusively breastfed up to six months', based on recall from birth. Exclusive breastfeeding rate was based on breastfeeding practice 24 h prior to the survey. Qualitative data was analysed through a deductive approach, using a pre-determined framework on determinants of breastfeeding. RESULTS: This study revealed an exclusive breastfeeding rate of 62.8% (95% CI 53.9, 71.7); dropping from 74% in the 0-1-month age group to 33% in the 4-5 months group. Triangulation of qualitative and quantitative data revealed enabling factors for primarily breastfeeding practice included mothers receiving support during their first breastfeed, pregnant women being provided with information on the benefits of the practice, counselling by nurses, support from husbands, and women's awareness of how their friends and family members fed their own babies. The main barriers were a lack of encouragement by husbands, women's perception that their infants' stools were abnormal or that they were not producing enough breast milk. CONCLUSIONS: Although the exclusive breastfeeding may have risen over recent years, a gap remains compared to World Health Organization recommendations. According to the breastfeeding determinants identified in this study, promotion of counselling by a nurse, encouragement of husbands' support, and improve knowledge of mothers on breastfeeding are recommended to be incorporated in the design of future health programs.

Cloning and expression of a cocaine-sensitive rat dopamine transporter.

The action of dopamine and other monoamine neurotransmitters at synapses is terminated predominantly by high-affinity reuptake into presynaptic terminals by specific sodium-dependent neurotransmitter transport proteins. A complementary DNA encoding a rat dopamine transporter has been isolated that exhibits high sequence similarity with the previously cloned norepinephrine and gamma-aminobutyric acid transporters. Transient expression of the complementary DNA in HeLa cells confirms the cocaine sensitivity of this transporter.

Alternative RNA processing: determining neuronal phenotype.

On the basis of an analysis of the human and rat calcitonin genes and of a related gene, alternative RNA processing represents a developmental strategy of the brain to dictate tissue-specific patterns of polypeptide synthesis. This regulation allows the calcitonin gene to generate two messenger RNA's, one encoding the precursor of a novel neuropeptide, referred to as CGRP, which predominates in the brain, and the second encoding the precursor to the hormone calcitonin which predominates in thyroid C cells. The distribution of CGRP in the central and peripheral nervous system and in endocrine and other organ systems suggests potential functions in nociception, ingestive behavior, cardiovascular homeostasis, and mineral metabolism.

Expression in brain of a messenger RNA encoding a novel neuropeptide homologous to calcitonin gene-related peptide.

As a consequence of alternative RNA processing events, a single rat gene can generate messenger RNA's (mRNA's) encoding either calcitonin or a neuropeptide referred to as alpha-type calcitonin gene-related peptide (alpha-CGRP). An mRNA product of a related gene has been identified in rat brain and thyroid encoding the protein precursor of a peptide differing from alpha-CGRP by only a single amino acid. The RNA encoding this peptide, which is referred to as beta-CGRP, appears to be the only mature transcript of the beta-CGRP gene. Hybridization histochemistry reveals a similar distribution of alpha- and beta-CGRP mRNA's, but their relative levels of expression vary in different cranial nerve nuclei. Thus beta-CGRP is a new member of a family of related genes with potential functions in regulating the transduction of sensory and motor information.

Maggot debridement therapy with Lucilia cuprina: a comparison with conventional debridement in diabetic foot ulcers.

This is prospective case-control study of more than 18 months performed to assess the effectiveness of maggot debridement therapy (MDT) with the sterile larvae of Lucilia cuprina (a tropical blowfly maggot) for the treatment of diabetic foot ulcers. Literature thus far has only reported results with the temperate maggot, Lucilia sericata. This study documents outcome in diabetic foot wounds treated with maggot debridement versus those treated by conventional debridement alone. In this series of 29 patients treated with MDT, 14 wounds were healed, 11 were unhealed and 4 were classified under others. The control group treated by conventional debridement had 30 patients of which 18 wounds were healed, 11 unhealed and 1 classified under others. There was no significant difference in outcome between the two groups. The conclusion that can be made from this study is that MDT with L. cuprina is as effective as conventional debridement in the treatment of diabetic foot ulcers. It would be a feasible alternative to those at high risk for surgery or for those who refuse surgery.

G protein ßγ subunits play a critical role in the actions of amphetamine.

Abnormal levels of dopamine (DA) are thought to contribute to several neurological and psychiatric disorders including drug addiction. Extracellular DA levels are regulated primarily via reuptake by the DA transporter (DAT). Amphetamine, a potent psychostimulant, increases extracellular DA by inducing efflux through DAT. Recently, we discovered that G protein ßγ subunits (Gßγ) interact with DAT, and that in vitro activation of Gßγ promotes DAT-mediated efflux. Here, we investigated the role of Gßγ in the actions of amphetamine in DA neurons in culture, ex vivo nucleus accumbens (NAc), and freely moving rats. Activation of Gßγ with the peptide myr-Ser-Ile-Arg-Lys-Ala-Leu-Asn-Ile-Leu-Gly-Tyr-Pro-Asp-Tyr-Asp (mSIRK) in the NAc potentiated amphetamine-induced hyperlocomotion, but not cocaine-induced hyperlocomotion, and systemic or intra-accumbal administration of the Gßγ inhibitor gallein attenuated amphetamine-induced, but not cocaine-induced hyperlocomotion. Infusion into the NAc of a TAT-fused peptide that targets the Gßγ-binding site on DAT (TAT-DATct1) also attenuated amphetamine-induced but not cocaine-induced hyperlocomotion. In DA neurons in culture, inhibition of Gßγ with gallein or blockade of the Gßγ-DAT interaction with the TAT-DATct1 peptide decreased amphetamine-induced DA efflux. Furthermore, activation of Gßγ with mSIRK potentiated and inhibition of Gßγ with gallein reduced amphetamine-induced increases of extracellular DA in the NAc in vitro and in freely moving rats. Finally, systemic or intra-accumbal inhibition of Gßγ with gallein blocked the development of amphetamine-induced, but not cocaine-induced place preference. Collectively, these results suggest that interaction between Gßγ and DAT plays a critical role in the actions of amphetamine and presents a novel target for modulating the actions of amphetamine in vivo.

A reentrant loop domain in the glutamate carrier EAAT1 participates in substrate binding and translocation.

To investigate the structural determinants underlying transport by the glutamate transporter EAAT1, we mutated each of 24 highly conserved residues (P392 to Q415) to cysteine. A majority of these substituted cysteines react with the sulfhydryl-modifying reagent MTSEA, suggesting that they reside in an aqueous environment. The impermeant reagents MTSES and MTSET react with residues at each end of the domain (A395C and A414C), supporting a model that places these residues near the extracellular surface. Substrates and inhibitors block the reaction between MTS derivatives and A395C, and the cosubstrate, sodium, slows reaction of MTSEA with Y405C and E406C. From these results, we propose that this domain forms a reentrant membrane loop at the cell surface and may comprise part of the translocation pore for substrates and cotransported ions.